To date, immune-related diseases such as, in particular, infectious diseases and autoimmune disorders are one of the biggest challenges for both human and animal health. The prevention and treatment of this kind of diseases is possible at various levels of the pathogenic mechanism underlying this kind of diseases. One approach is to target the ultimate causative agent which means, in case of infectious diseases, the pathogen and in case of autoimmune disease the respective autoreactive antibodies or lymphocytes. Although this is a reasonable and in quite a number of cases successful approach, however, it still has some drawbacks. These drawbacks are, among others, in case of infectious diseases a shortage of means addressing the pathogen, in particular when it comes to viruses, and an increasing number of resistant strains of various bacteria against a number of antibiotics available for the time being, and in case of autoimmune disorder, the need for constant removal or at least neutralization of autoimmune antibodies or autoreactive immune cells with the autoimmune antibodies being the last element of a cascade and thus being rather abundant requiring a therapeutic approach which is also adequate in terms of titres of neutralizing agents needed.
A quite opposite approach for the treatment of this kind of diseases is to modify the immune system such as to treat or even prevent this kind of diseases. The more upstream an immune system modifying agent is active, the broader its potential field of use is. One such element which is a preferred molecule of consideration insofar, is the T cell receptor (TCR) as described in M. M. Davis, J. J. Boniface, Z. Reich, D. Lyons, J. Hampl, B. Arden, and Y. Chien: Ligand recognition by alpha beta T cell receptors Annu. Rev. Immunol. 1998. 16: 523-544.
A high level of TCR expression on T lymphocyte surfaces is required in most infections for complete removal of the pathogen. The particular relevance of T cell receptor expression insofar is further illustrated by the fact that it takes ten times more low avidity T cells to control infection than high avidity T cells which is particularly important for the development of vaccines as described by Derby, M., Alexander-Miller, M., Tse, R., and Berzofsky, J: High-avidity CTL exploit two complementary mechanisms to provide better protection against viral infection than low-avidity CTL. J Immunol 2001. 166: 1690-1697. The low surface display of antigenic peptides during some virus infection such as, e.g., human immune deficiency virus (HIV) or by hepatitis C virus (HCV) shows that high avidity T cells are needed to protect from infections after vaccination. On the other hand, in autoimmune diseases, obviously, self-antigens are over-recognized by such T cell receptor which, in turn, triggers an over boarding immune response with severe concomitant physiological responses. Insofar, for this kind of disease a blocking of increased surface expression of T cell receptors is highly desirable.
A problem underlying the present invention was thus to provide means for the treatment of immune-related diseases, and more particularly for the treatment and/or prevention of infections and/or autoimmune disorders. In a further aspect, the present invention was to provide means for increasing the T cell receptor expression on T lymphocytes.